Safety hook with immobilizable locking lever

ABSTRACT

A safety hook in accordance with the invention comprises a body closed by a pivoting finger which can be prevented from rotating by a transverse locking lever. The locking lever is articulated on a lever pivot on the pivoting finger and has a notch engaging over a front lug of the body in the locked position, into which it is biased by a spring. A mobile abutment can be selectively positioned on the locking lever to prevent it pivoting in the unlocking direction. This assures reliable locking by means of a Locking lever that is easy to manipulate and immobilize.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention concerns safety hooks which lock automatically inwhich locking is assured by a transverse locking lever engaging betweena pivoting closure finger and an opposite portion of the safety hookbody to selectively prevent pivoting of the locking finger in theopening direction.

2. Description of the Prior Art

Safety hooks of the above kind that are locked automatically by atransverse lever are described in documents FR 2 439 330 A and FR 2 485658 A.

In both of the above documents, the safety hook comprises a safety hookbody having an opening selectively closed by a pivoting fingerarticulated at its first end about a transverse rotation pivot, with atransverse locking lever mounted to be able to pivot about a lever pivotbetween a locking position, in which it is engaged between the pivotingfinger and an opposite portion of the body to prevent rotation of thepivoting finger and toward which it is biased by spring means, and anunlocked position, in which it releases the pivoting finger so that itcan rotate in its opening direction. The pivot of the locking lever isin said opposite portion of the body, and the free end of the lockinglever engages over the pivoting finger.

In document FR 2 485 658 A, the locking lever is generally rectilinearand is entirely engaged between the pivoting finger and the oppositeportion of the body, near the free end of the pivoting finger. As aresult, the locking lever reduces the opening capacity of the safetyhook, and constitutes a component that is relatively inconvenient tooperate. This device is therefore not suitable for mountaineering use orfor working in high places, where safety conditions must be compliedwith without necessitating difficult and irksome intervention by theuser. What is more, there is nothing to prevent pivoting of the lockinglever, which can therefore be unlocked unintentionally.

In document 2 439 330 A, the transverse locking lever is at a greaterdistance from the free end of the pivoting finger, which improves theopening capacities. Also, the locking lever is L-shaped with alongitudinal branch that projects radially beyond the opposite portionof the body, which facilitates manipulating the locking lever. However,the free end of the locking lever comprises two parallel branchesdisposed each on opposite sides of the pivoting finger to engage overlateral bosses on the pivoting finger to lock the safety hook. Theparallel branches at the end of the locking lever constitute relativelyweak components that may be deformed in use. If they are deformed awayfrom each other, there is a risk of inhibiting all locking capacity ofthe locking lever, so compromising the reliability and the safety of thesafety hook. What is more, the locking lever projects away from the bodyin an exaggerated manner and constitutes a protruding component that caninterfere with use and to which force can be applied unintentionally.

In the above document, a sliding ring, mounted on the opposite portionof the body, can immobilize the locking lever to prevent it pivotingtoward the unlocked position. The drawback of this is that it istherefore necessary to manipulate the locking ring each time so that thelocking lever can then be manipulated to unlock the safety hook.

The problem addressed by the present invention is that of the designinga new hook structure which is locked automatically by a transverselocking lever, which assures both reliable and effective locking and amaximum opening capacity of the safety hook, and which assures selectiveimmobilization or permanent releasing of the locking lever, enabling theuser to choose between single locking or double locking. The change fromthe immobilized state to the released state must be effected simply andquickly by intentional action of the user.

The invention equally aims to design a safety hook structure of theabove kind that is particularly simple and inexpensive to manufacture.

SUMMARY OF THE INVENTION

To achieve the above and other objects, the invention consists in asafety hook which locks automatically including a safety hook bodyhaving an opening closed by a pivoting finger articulated at its firstend about a transverse rotation pivot, a transverse locking levermounted to pivot about a lever pivot between a locking position towardwhich it is biased by spring means and in which it is engaged betweenthe pivoting finger and an opposite portion of the body to preventrotation of the pivoting finger, and an unlocked position in which itreleases the pivoting finger so that it can rotate in the openingdirection, and immobilizing means for selectively immobilizing thelocking lever against rotation away from the locked position to preventunlocking of the safety hook; according to the invention: theimmobilizing means is a mobile abutment, mounted on the locking lever,and movable on guides between an immobilizing position in which it bearsagainst a portion of the body to oppose pivoting of the locking lever,and a release position in which it remains away from the portion of thebody to allow unlocking pivoting of the locking lever.

In one embodiment, the guides include a shallow first notch in which themobile abutment is engaged in he immobilizing position, and a deepernotch in which he mobile abutment can engage in the release position, henotches extending in a generally radial direction way from the body.

The mobile abutment is advantageously biased by a spring which pushes itaway from the body, either into the bottom of the first notch or towardthe bottom of the second notch.

The spring preferably also biases the locking lever toward its lockedposition and pushes the mobile abutment away from the body.

Other objects, features and advantages of the present invention willemerge from the following description of particular embodiments, givenwith reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a first embodiment of a safety hook inaccordance with the present invention, closed and locked, with thelocking lever immobilized.

FIG. 2 is a plan view in section taken along the line A—A in FIG. 1.

FIG. 3 is a front view of the safety hook from FIG. 1 closed and lockedwith the locking lever released.

FIG. 4 is a front view of the safety hook from FIG. 1 closed andunlocked.

FIG. 5 is a front view of the safety hook from FIG. 1 open.

FIG. 6 is a front view of a second embodiment of a safety hook inaccordance with the present invention, closed and locked with thelocking lever immobilized.

FIG. 7 is a front view of the safety hook from FIG. 6 closed and lockedwith the locking lever released.

FIG. 8 is a front view of the safety hook from FIG. 6 closed andunlocked.

FIG. 9 is a front view of the safety hook from FIG. 6 open.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In both embodiments shown in the figures, a safety hook in accordancewith the invention which locks automatically comprises a safety hookbody 1 having a closed first loop 2 and an opening second loop 3. Theopening loop 3 comprises an opening 4, delimited by a first end 5 and asecond end 6 of the body. The opening 4 is selectively closed by apivoting finger 7 articulated at its first end 8 to the first end 5 ofthe body about a transverse rotation pivot 9. In the closed positionshown in FIG. 1, the second end 10 of the pivoting finger 7 engages overthe second end 6 of the body.

In the embodiments shown, the safety hook has a particular andadvantageous shape. Thus, considering the longitudinal axis I—I of thesafety hook, joining the center of the closed first loop 2 and the top11 of the opening second loop 3, the body 1 comprises a longitudinalbranch 12 generally parallel to and relatively close to the axis I—I,whereas the pivoting finger 7 and the corresponding oblique secondbranch 13 of the body 1 diverge from the longitudinal axis I—I. From thetop 11, the oblique second branch 13 extends obliquely to the second end6 of the body. The longitudinal branch 12 of the body 1 has at its basean oblique portion 14 which converges progressively with thelongitudinal axis I—I to form an external recess 115 in the portion ofthe body 1 opposite the pivoting finger 7.

Because of the oblique second branch 13 and the oblique portion 14 ofthe body 1, the opening second loop 3 is elongate along an oblique axisII—II with a back of the opening second loop 3 constituted by the top 11and the longitudinal branch 12 of the body, the back being opposite theopening 4 closed by the pivoting finger 7. When the pivoting finger 7 isopen, as shown in FIG. 5 or FIG. 9, the pivoting finger 7 bears againstthe oblique portion 14 of the body 1, and in this way frees a largespace within the opening second loop 3. The safety hook then constitutesa wide open hook which is very easy to fit to an anchor member such as abar, a ring, a cable, a rope.

The oblique portion 14 and the pivoting finger 7 are advantageouslycurved as shown in the figures. However, the radially outermost portion107 of the pivoting finger 7 is set back from the line joining thefarthest projecting areas 106 and 102 of the body 1 on either side ofthe pivoting finger 7. The pivoting finger 7 is therefore not rotated ifthe two protruding areas 106 and 102 of the safety hook are in contactwith a plane surface.

The safety hook in accordance with the invention further comprises atransverse locking lever 15 mounted to pivot about a lever pivot 16 atan intermediate position on the pivoting finger 7. In the advantageousembodiment shown, the lever pivot 16 is nearer the first end 8 than thesecond end 10 of the pivoting finger 7, for example about one fifth ofthe length of the pivoting finger 7 from the first end 8 of the pivotingfinger 7.

The locking lever 15 has an engaging part 17 for co-operating with acorresponding bearing area 18 in a portion of the body 1 opposite thepivoting finger 7.

In the embodiment shown in the figures, the engaging part 17 comprisesat least one notch formed in a ramp consisting of the bottom edge 19 ofthe locking lever, and the bearing area 18 of the body 1 comprises atleast one front lug projecting from the body 1 parallel to the leverpivot 16. The bottom edge 19 of the locking lever 15 is generallyperpendicular to the longitudinal axis I—I of the safety hook, while thenotch 17 constituting the engaging part is generally longitudinal, thatis to say parallel to the longitudinal axis I—I. In the locked positionshown in FIG. 1, the front lug 18 engaged in the notch 17 preventsmovement of the locking lever 15 toward the right, and thus locks thesafety hook by opposing pivoting of the pivoting finger 7, which is heldin the closed position.

Thus, in the locked position, the engaging part 17 and the correspondingbearing area 18 of the body 1 oppose transverse movement of the lockinglever 15 and the pivoting finger 7.

In the unlocked position shown in FIG. 4, the locking lever 15 haspivoted, and the engaging part 17 or notch has escaped from the bearingarea 18 or front lug of the body 1 to allow transverse movement of thelocking lever 15 and to allow the pivoting finger 7 to pivot in theopening direction.

As shown in FIG. 2, the locking lever 15 in this embodiment is a platebent to a U-shape with two parallel branches 21 and 22 respectivelyconnected by a bearing wall 20. The branch 21 faces the front face 23 ofthe body 1, while the branch 22 faces the rear face 24 of the body 1.The free ends of the branches 21 and 22 are joined by the lever pivot 16which allows the locking lever 15 to pivot but prevents any risk of thebranches 21 and 22 moving apart.

As shown in FIG. 1, in which it is seen from the front, the lockinglever 15 is preferably generally L-shaped with a transverse lockingbranch 25 between the lever pivot 16 on the pivoting finger 7 and theengaging part 17, and with a longitudinal manipulator branch 26projecting radially beyond the opposite portion of the body 1, althoughit preferably remains within the external recess 115 to avoid itprotruding in an exaggerated fashion. The longitudinal manipulatorbranch 26 is extended longitudinally toward the top 11 of the body 1 ofthe safety hook beyond the transverse area of the safety hook containingthe lever pivot 16. The bearing wall 20 is extended by the longitudinalmanipulator branch 26 to constitute a more comfortable bear for theuser, who has to depress the bearing wall 20 to pivot the locking lever15 between the locked position (FIG. 1) and the unlocked position (FIG.4).

In the embodiment shown, because of the position of the engaging part 17in the form of a notch in the bottom edge 19 of the locking lever 15,when it rotates in the unlocking direction, the locking lever 15 pivotsin the direction opposite the rotation of the pivoting finger 7 in theopening direction: as shown in FIG. 1, to unlock the safety hook, thelocking lever 15 pivots anti-clockwise, while to open the hook, thepivoting finger 7 pivots clockwise. As a result, to unlock the safetyhook, the user applies a force F1 to the bearing wall 20 of the lockinglever 15 in a direction radially toward the center of the safety hook.At the same time, or slightly afterwards, the user applies to thepivoting finger 7 a force F2, also radially toward the center of thesafety hook but in the opposite direction to the force Fl, to move thepivoting finger 7 to the open position. This makes it very easy tounlock and open the safety hook by the user simultaneously applyingpressure to generate the forces F1 and F2.

Alternatively, the engaging part 17 could have a different shape, forexample it could be a slot in the locking lever 15, in which caseunlocking the safety hook would imply rotating the locking lever 15clockwise in the outward direction, to unlock the safety hook byrotating the locking lever 15 in the same direction as the rotation thatopens the pivoting finger 7.

Referring again to FIG. 2, it can be seen that the bearing area of thebody is in reality provided by a front first lug 18, and by acorresponding rear second lug 118. The front lug 18 cooperates with anotch 17 as shown in FIG. 1, while the rear lug 118 cooperates with asimilar notch formed in the second branch 22 of the locking lever 15(not shown in the figure).

FIG. 1 also shows a spring 27 engaged between the locking lever 15 andthe body 1 to bias the locking lever 15 into the locked position inwhich the notch 17 is in bearing engagement with the front lug 18.

In the embodiment shown, the spring 27 is a curved flexible leaf springwith two generally parallel branches 28 and 30 with a first end of afirst branch 28 fixed to the locking lever 15 in a fixing area 29 andits second end bears against the outside face of the longitudinal branch12 of the body 1 and is bent so that it connects to a second branch 30generally parallel to the first branch 28. The first branch 28 of thespring 27 is therefore functionally engaged between the body 1 and thelocking lever 15 to push the locking lever 15 toward its lockedposition.

In the embodiments shown, the safety hook further comprises immobilizingmeans for selectively immobilizing the locking lever 15 against rotationand preventing unlocking of the safety hook.

In the figures, the immobilizing means comprise a mobile abutment 31,mounted on the locking lever 15, and movable on guides 32 between animmobilizing position, shown in FIG. 1, in which the mobile abutment 31bears against a portion of the body 1 to oppose pivoting of the lockinglever 15, and a release position shown in FIG. 3, in which the mobileabutment 31 is moved away from the portion of the body 1 to authorizeunlocking pivoting of the locking lever 15.

The mobile abutment 31 is a front-to-back pin mounted to slide in twolateral slots 33 and 133 (FIG. 2) forming the guides 32 in respectiveparallel branches 21 and 22 of the locking lever 15. Each slot, forinstance the lateral slot 33, has a shallow first notch 34 in which themobile abutment 31 is engaged in the immobilizing position, and a deepersecond notch 35 in which the mobile abutment 31 can engage in therelease position. The notches 34, 35 extend in a generally radialdirection away from the body 1.

The second branch 30 of the spring 27 is functionally engaged betweenthe body 1 and the mobile abutment 31 to push the mobile abutment 31away from the body 1, either into the bottom of the first notch 34 ortoward the bottom of the second notch 35.

How the safety hook works will now be explained with reference to FIGS.1 to 5.

In the closed, locked and immobilized position shown in FIG. 1, themobile abutment 31 is engaged in the first notch 34 of the lateral slot33, into which it is pushed by the spring 27. In this first notch 34,the mobile abutment 31 is in the immediate vicinity of the lateral faceof the body 1, preventing rotation of the locking lever 15 in theclockwise direction.

In FIG. 3, the mobile abutment 31 has moved into the second notch 35 ofthe lateral slot 33. The mobile abutment 31 is then away from the body1, and allows the locking lever 15 to rotate counterclockwise. Thelocking lever 15 remains in the locked position, however, into which itis biased by the spring 27, preventing pivoting of the pivoting finger7.

FIG. 4 shows the safety hook unlocked and closed: the user has pivotedthe locking lever 15 in the unlocking direction 36 about its lever pivot16, against the return force exerted by the spring 27, moving the notch17 away from the front lug 18. The pivoting finger 7 remains in theclosed position, however, into which it is biased by a return springthat is not shown in the figures.

In FIG. 5, the user has pivoted the pivoting finger 7 to its openposition, in the direction of the arrow 37 and about its transverserotation pivot 9, freeing the opening 4. During this movement, the frontlug 18 can slide on the ramp consisting of the bottom edge 19 of thelocking lever 15.

In the embodiment shown in FIGS. 1 to 5, and as seen best in FIG. 2, themobile abutment 31 is a front-to-back pin with two heads 38 and 138 atits ends which are wider than tile portion of the lateral slot 33including the notches 34 and 35. An end portion 39 of the lateral slot33 is widened for the end heads 38 and 138 to pass through duringassembly. The end heads 38 and 138 constitute the manipulator memberwhich the user employs to move the mobile abutment 31 between theimmobilizing position and the release position.

In the embodiment shown in FIGS. 6 to 9, the mobile abutment 31 is movedbetween the immobilizing position shown in FIG. 6 and the releaseposition shown in FIGS. 7 to 9 by a slider 40 having a head 41 extendingto the outside of the bearing wall 20 of the locking lever 15, andhaving a fork 42 engaged on either side of the front-to-back pin formingthe mobile abutment 31. The slider 40 slides longitudinally in alongitudinal slot formed in the bearing wall 20 of the locking lever 15,between the immobilizing position shown in FIG. 6 and the releaseposition shown in FIGS. 7 to 9.

Otherwise, the safety hook shown in FIGS. 6 to 9 comprises the samecomponents as the hook shown in FIGS. 1 to 5, and works in exactly thesame manner, as shown in the figures.

In another embodiment, the lever pivot 16 is in the portion of the body1 opposite the pivoting finger 7. The locking lever 15 then has anengaging part co-operating with a corresponding bearing area of thepivoting finger 7 in the locked position to oppose opening pivoting ofthe pivoting finger 7, the engaging part escaping from the bearing areaof the pivoting finger 7 in the unlocked position of the locking lever15 to allow the pivoting finger 7 to pivot in the opening direction.This embodiment corresponds to a structure of the locking lever 15 asdescribed in document FR 2 439 330 A, to which reference may usefully bemade.

The particular shape of the body 1 of the safety hook, comprising anexternal recess 115 in the body portion opposite the pivoting finger 7,associated with the fact that the locking lever 15 has a longitudinalmanipulator branch 26 which remains inside the external recess 115 ofthe body 1, constitutes an advantageous combination that can be usedindependently of the presence or absence of means for immobilizing thelocking lever 15, and regardless of the position chosen for the leverpivot 16 on the pivoting finger 7 or on the opposite portion of the body1.

The present invention is not limited to the embodiments explicitlydescribed, but includes variants and generalizations thereof within thescope of the following claims.

There is claimed:
 1. A safety hook which locks automatically including asafety hook body having an opening closed by a pivoting finger, thepivoting finger having a first end, the pivoting finger beingarticulated at said first end about a transverse pivot, a transverselocking lever mounted to pivot about a lever pivot on the pivotingfinger, between a locked position toward which it is biased by springmeans and in which it mechanically connects said pivoting finger with anopposite portion of said body to prevent rotation of said pivotingfinger, and an unlocked position in which the locking lever releasessaid pivoting finger so that the pivoting finger can rotate in theopening direction, and immobilizing means for selectively immobilizingsaid locking lever against rotation away from said locked position toprevent unlocking of said safety hook and comprising a mobile abutment,mounted on said locking lever, and movable on guides between animmobilizing position in which it bears against a portion of said bodyto oppose pivoting of said locking lever, and a release position inwhich it remains away from said portion of said body to allow unlockingpivoting of said locking lever.
 2. The safety hook claimed in claim 1wherein said guides include a shallow first notch in which said mobileabutment is engaged in said immobilizing position, and a deeper secondnotch in which said mobile abutment can engage in said release position,said notches extending in a generally radial direction away from saidbody.
 3. The safety hook claimed in claim 2 wherein said mobile abutmentis biased by a spring which pushes it away from said body, either intothe bottom of said first notch or toward the bottom of said secondnotch.
 4. The safety hook claimed in claim 3 wherein said spring alsobiases said locking lever toward its locked position and pushes saidmobile abutment away from said body.
 5. The safety hook claimed in claim3 wherein said spring is a curved flexible leaf spring with twogenerally parallel branches, with a first branch functionally engagedbetween said body and said locking lever to push said locking levertoward its locked position, and a second branch functionally engagedbetween said body and said mobile abutment to push said mobile abutmentaway from said body.
 6. The safety hook claimed in claim 1 wherein: saidlocking lever has two parallel branches joined by a bearing wall, saidguides are constituted by two lateral slots, each of which is in arespective one of said parallel branches, said mobile abutment is afront-to-back pin mounted to slide in said lateral slots.
 7. The safetyhook claimed in claim 6 wherein said mobile abutment comprises two endheads constituting a manipulator member enabling a user to move saidmobile abutment between said immobilizing position and said releaseposition.
 8. A safety hook as claimed in claim 6 further comprising aslider including a head projecting to the outside of said bearing wallof said locking lever and including a fork engaged in opposite sides ofsaid front-to-back pin forming said mobile abutment, and slidinglongitudinally in a longitudinal slot in said bearing wall of saidlocking lever between said immobilizing position and said releaseposition.
 9. The safety hook claimed in claim 1 wherein: said leverpivot is disposed at an intermediate position on said pivoting finger,said locking lever comprises an engaging part cooperating with acorresponding bearing area of said body in said locked position tooppose transverse movement of said locking lever and said pivotingfinger, said engaging part escaping from said bearing area of said bodyin said unlocked position of said locking lever to allow said pivotingfinger to pivot in the opening direction.